Kinds of innate immunity barriers are

Correct Answer: C

Rationale: The correct answer is C because both external barriers (Skin, Secretions, Mucous membranes) and internal defenses (Inflammatory response) are types of innate immunity. External barriers physically block pathogens from entering the body, while internal defenses involve cellular and molecular responses to eliminate pathogens. Choice A alone does not cover internal defenses, and choice B alone does not cover external barriers, making them individually incomplete. Choice D is incorrect as innate immunity does involve specific barriers and responses. Therefore, choice C is the best answer as it encompasses both types of innate immunity barriers.

Correct Answer: B

Rationale: The correct answer is B: 40-60%. Hematocrit represents the percentage of red blood cells in the blood. The normal range for hematocrit in a healthy adult is typically around 40-60%. Values below 40% may indicate anemia, while values above 60% may suggest conditions like dehydration or polycythemia. Choices A, C, and D are incorrect because they fall outside the normal range for hematocrit levels in a healthy adult.

Correct Answer: D

Rationale: The correct answer is D: Anemia. Anemia is the medical term for a condition where there is a decrease in the number of red blood cells or hemoglobin in the blood. The formation of abnormal red blood cells can lead to anemia, affecting the oxygen-carrying capacity of the blood. Leukocytosis (A) is an increase in white blood cells, thrombocytosis (B) is an increase in platelets, and hemolysis (C) is the breakdown of red blood cells, none of which specifically refer to the formation of abnormal red blood cells.

Correct Answer: B

Rationale: Barry Marshall drank a pure culture of H. pylori to demonstrate an association between H. pylori infection and gastric ulcers. This is because he wanted to prove the theory that the bacteria is a primary cause of stomach ulcers, contradicting the prevailing belief at the time. Choice A is incorrect because the direct link between H. pylori and gastric cancer was not the primary focus of his experiment. Choice C is incorrect as his goal was to show the bacterial link to ulcers, not to disprove stress as a factor. Choice D is incorrect because only choice B accurately reflects his intended purpose.

Correct Answer: A

Rationale: The correct answer is A: Selectins expressed on endothelial cells. Rolling of neutrophils on endothelial cells is a crucial step in the process of inflammation and immune response. Selectins are cell adhesion molecules expressed on endothelial cells that facilitate the initial interaction between leukocytes (such as neutrophils) and endothelial cells. This interaction allows for the rolling of neutrophils along the endothelial surface, which is essential for the subsequent steps of adhesion and transmigration into the tissues. Integrins (Choice B) are involved in the firm adhesion of leukocytes to endothelial cells, not in the initial rolling process. Chemokines (Choice C) such as CXCL-8 are signaling molecules that help in the recruitment of leukocytes but do not directly mediate the rolling process. TNF (Choice D) is a pro-inflammatory cytokine but is not directly involved in the rolling of neutrophils on endothelial cells.